MRI scans and neuropsychological test data of 80 elderly (greater than 50 years of age) inpatients and outpatients with DSM III major depression, 40 patients with NINCDS possible or probable Alzheimer's Disease and 40 age- matched controls will be compared at index and 2 year follow-up. MRI scans will be rated with the CERAD protocol. Volumetric measures will be determined for temporal lobes, superior temporal sulci, third ventricles and amygdala. Cross-sectional areas of mid-brain pons and mid-sagittal areas will be measured. Three major study questions are identified: 1) Do depressives have more cortical as well as subcortical abnormalities on MRI compared to normals and less than AD patients? 2) Do clinical variables in depressive (response to treatment for depression, neuropsychological performance, impairment of activities of daily living) correlate with severity of MRI changes? 3) What is the prognostic significance of MRI lesions in depressives. We hypothesize that greater extent of lesions will correlate with number of relapses, development of dementia and development of ADL impairment over 2 years. Finally, we propose to further characterize the language disorder of the dementia syndrome of depression and to correlate its extent with number of basal ganglia lesions, left temporal lobe volume and left superior temporal gyrus volume.